Hum, don't think so but keep tuned and someone might have your answer.
The finish plaster is normally white all the way through. It sounds like you are dealing with a pool that has been replastered by the method of putting a "brown coat"/"scratch coat" (the gray plaster you noted) over the original finish plaster surface, and a new finish coat of white plaster on top of that. The scratch coat more like a thin concrete than plaster (doesn't have the white marble dust in it) and is used to get a better bond to the old surface.
try a concrete stain to blend the whitened area to whatever color it was before
No, plaster of Paris and white cement are not the same. Plaster of Paris is a porous material that will disintegrate outside in the rain. White cement is more durable and should last outside in the rain.
Just paint it white!!
There are many types (formulas/components) of Plaster. "Normal" plaster, if there is such a thing is usually White. Plaster is easily colored by using color additives when it is mixed.
use yellow stain on white hat remover
The japanese put white plaster on the walls because it is fireproof
Not with concrete you need Pool plaster which uses moisture to dry where concrete uses air to dry(somewhat comlicated)Your local pool company should be able to supply you with pool plaster from there go onto the internet to National spa & pool the process is in the technical section.Good Luck this should be done in full by a professional but the only way to learn is to give it a try. Kenny Kummer E.M.Systems
Use stain remover. Use stain remover.
cause it does this is a scientific reason therefore the white wine sinks into the carpet or what ever you have the red stain is and when the white wine sinks into the stain it releases the red stain particles and the red stain particles mix in with the white wine therefore the red stain is vanished
It makes very little difference
It makes very little difference